For some considerable time I, like many other pediatricians, have been dissatisfied with the charts in general use at the present time, because they represent the absolute changes only of the conditions which we intend to record graphically, but fail to represent these in their relative, or better percentages of values.
Let us take, for instance, the growth charts for normal and healthy infants taken from the chapter on growth by Robertson,1 and we shall see that one group of male infants, whose weight at birth was 5 pounds 6 ounces (2,438 gm.), will weigh 14 pounds 2 ounces (6,407 gm.) at the completion of the first year; a second group whose weight at birth was 6 pounds 4 ounces (2,841 gm.) will weigh 16 pounds 6 ounces (7,433 gm.) at the completion of the first year; a third group which he calls the standard average, whose weight at